• Title/Summary/Keyword: ship collision avoidance

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Development of a Navigation Control Algorithm for Mobile Robots Using D* Search and Fuzzy Algorithm (D* 서치와 퍼지 알고리즘을 이용한 모바일 로봇의 충돌회피 주행제어 알고리즘 설계)

  • Jung, Yun-Ha;Park, Hyo-Woon;Lee, Sang-Jin;Won, Moon-Cheol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.8
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    • pp.971-980
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    • 2010
  • In this paper, we present a navigation control algorithm for mobile robots that move in environments having static and moving obstacles. The algorithm includes a global and a local path-planning algorithm that uses $D^*$ search algorithm, a fuzzy logic for determining the immediate level of danger due to collision, and a fuzzy logic for evaluating the required wheel velocities of the mobile robot. To apply the $D^*$ search algorithm, the two-dimensional space that the robot moves in is decomposed into small rectangular cells. The algorithm is verified by performing simulations using the Python programming language as well as by using the dynamic equations for a two-wheeled mobile robot. The simulation results show that the algorithm can be used to move the robot successfully to reach the goal position, while avoiding moving and unknown static obstacles.

A Study on Marine Application of Wireless Access in Vehicular Environment (WAVE) Communication Technology (차량용 무선통신기술(WAVE)의 해상적용에 관한 연구)

  • Kang, Won-Sik;Jeon, Soon-Bae;Kim, Young-Du
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.24 no.4
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    • pp.445-450
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    • 2018
  • AIS is the most important navigation equipment for the identification of other ships, etc. However, the AIS overload problem has been raised recently due to an increase in AIS equipped vessels. The government is planning to introduce the wireless LTE network at 100 km offshore as part of the SMART-Navigation project. Continuous development and dissemination of the services available through such platforms will be necessary to achieve major goals such as marine accident prevention and environmental protection. In this study, we applied a WAVE communication system, which could be the basis for the development of such services. As a result, reliable data transmission was confirmed for a range of communication of approx. 5 miles, although the service was limited to 1 km in road traffic. Therefore, it is expected that WAVE communication technology will be used to prevent marine accidents through such efforts as collision avoidance and the transfer of marine safety information between ships.

The Relative Distance in Taking Action for Collision Avoidance Maneuver of the Stand-on Vessel (피항조선시의 유지선 피항개시거리에 관한 연구)

  • 김기윤
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.32 no.4
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    • pp.363-371
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    • 1996
  • The Steering and Sailing Rules of International Regulations for Preventing Collisions at Sea now in use direct the best aid - action to avoid collision by the stand - on vessel. But these rules do not refer to the safety relative distance between two vessels when she should take such action. In this paper, the author analyzed the ship's collision avoiding actions from the viewpoint of ship motions and worked out mathematical formulas to calculate the relative distances necessary for taking action to avoid collision. Figuring out the values of maneuvering indices through experiments of 11 actual ships of small, medium, large and mammoth size, the author applied these values to the calculating formulas and calculated the minimum relative distances. The main results are as follows: 1. It was confIrmed that the stand - on vessel should keep the greatest relative distance for taking best aid - action to avoid collision when the cross angle of course was $90^{\circ}$ and near it(70-$90^{\circ}$ ). 2. When the cross angle of course was $90^{\circ}$ , the minimum relative distance of small vessel(GT: 160-650tons) was found to be more than about 6.8 times of her own length, and those of medium(GT : 2,300-3,500tons), large(GT : 22,OOO-62,OOOtons) and mammoth(GT : 91,000-139,000tons) vessels were found to be more than about 9.0 times, about 5.4 times and about 6.8 times of their own lengths. 3. It was confIrmed that collision danger was greater when crossing angle was obtuse than in an acute angle, therefore greater relative distance was to be kept by the stand - on vessel for taking best aid - action to avoid collision in the case of the obtuse angle. 4. In every vessels, in the case of $90^{\circ}$ cross angle of course the safety minimum relative distance was found to be more than about 9.0 times of their own lengths.

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An Evaluation of Effectiveness for Providing Safety Navigation Supporting Service : Focused on CPA/TCPA Information Supplying Service (안전 항해 지원 서비스 제공에 대한 유용성 평가(II) : CPA/TCPA 정보 제공 서비스를 대상으로)

  • Hwang, Hun-Gyu;Kim, Bae-Sung;Shin, Il-Sik;Lee, Jang-Se;Yu, Yung-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.9
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    • pp.1788-1795
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    • 2017
  • In this paper, we proposed a service that provides CPA/TCPA information to ships, without ARPA/ATA devices to support decision making of the navigator for maritime safety based on various services at shore and off-shore. To verify the proposed service, we use SiNAS (scenario-based simulator for NAS) with CPA/TCPA information providing software to evaluate its usability, because executing the test in real ship has many limitations and difficulties. To do this, we specify two simulation scenarios for the required purpose, and we liaise twelve participants with various navigation experience to conduct the simulations. Also, we analyze the results of simulation using mission success or not, the minimum approaching distance with the target ship, the time of a recognition the target ship, the time of a first action for collision avoidance with the target ship, and so on. Then, we evaluate usability of the proposed service based on the three elements which are effectiveness, efficiency and satisfaction.

Path-following Control for Autonomous Navigation of Marine Vessels Considering Disturbances (외력을 고려한 선박의 자율운항을 위한 경로추종 제어)

  • Lee, Sang-Do
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.27 no.5
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    • pp.557-565
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    • 2021
  • Path-following control is considered as one of the most fundamental skills to realize autonomous navigation of marine vessels in the ocean. This study addresses with the path-following control for a ship in which there are environmental disturbances in the directions of the surge, sway, and yaw motions. The guiding principle and back-stepping method was utilized to solve the ship's tracking problem on the reference path generated by a virtual ship. For path-following control, error dynamics is one of the most important skills, and it extends to the research fields of automatic collision avoidance and automatic berthing control. The algorithms for the guiding principles and error variables have been verified by numerical simulation. As a result, most error variables converged to zero values with the controller except for the yaw angle error. One of the most interesting results is that the tracking errors of path-following control between two ships are smaller than the existing safe passing distances considering interaction forces from near passing ships. Moreover, a trade-off between tracking performance and the ship's safety should be considered for determining the proper control parameters to prevent the destructive failure of actuators such as propellers, fins, and rudders during the path-following of marine vessels.

Improved Dynamic Window Approach With Path-Following for Unmanned Surface Vehicle (무인수상정을 위한 경로선 추종이 가능한 개선된 Dynamic Window Approach)

  • Kim, Hyogon;Yun, Sung-Jo;Choi, Young-Ho;Lee, Jung-Woo;Ryu, Jae-KWan;Won, Byong-Jae;Suh, Jin-Ho
    • IEMEK Journal of Embedded Systems and Applications
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    • v.12 no.5
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    • pp.295-301
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    • 2017
  • Recently, autonomous navigation technology, obstacle recognition, and obstacle collision avoidance technology are actively being developed for an unmanned surface vehicle (USV). The path to move from the current location to the destination should be planned, in order for an USV to autonomously operate safely to its destination. The dynamic window approach (DWA) is a well-known navigation scheme as a local path planning. The DWA algorithm derives the linear velocity and angular velocity by evaluating the destination direction, velocity, and distance from the obstacle. However, because DWA algorithm does not consider tracking the path, when using only the DWA algorithm, the ship may navigate away from the path line after avoiding obstacles. In this paper, we propose an improved DWA algorithm that can follow path line. And we implemented the simulation and compared the existing DWA algorithm with the improved DWA algorithm proposed in this paper. As a result, it is confirmed that the proposed DWA algorithm follows the path line better.

Intelligent Navigation Information Fusion Using Fuzzy Expert System (퍼지 전문가 시스템을 이용한 지능형 항행 정보 융합)

  • Kim, Do-Yeon;Yi, Mi-Ra
    • Journal of the Korea Society of Computer and Information
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    • v.15 no.11
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    • pp.47-56
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    • 2010
  • In navigation, officers receive data about inside and outside of ship from several devices(ex, GPS / AIS / ECDIS / ARPA Radar / etc) in bridge, and use it to recognize and predict safety situations. However, observation work of a officer is still hard for a torrent of data from several devices, and the problem of inconsistent data among the devices. In previous research, we presented the conceptual model of Intelligent Navigation Safety Information System based on information fusion, and showed the example of the conceptual model using CF (Certainty Factor) expert system to solve this problem. The information fusion technology needs various reasoning skills, and CF expert system is not enough to express ambiguous or indefinite factors. In this paper, we propose the concept of an intelligent navigation information fusion using fuzzy expert system to describe the ambiguous factors, and show the validity of applying fuzzy expert system to the Navigation Safety Information System through the design and implementation of the proposed concept.

Study on the Establishment of the Separation Distance between Anchored Ships in Jinhae Bay Typhoon Refuge (진해만 태풍 피항지 정박 선박간 이격거리 설정에 관한 연구)

  • Won-Sik Kang;Ji-Yoon Kim;Dae-Won Kim
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.29 no.4
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    • pp.338-347
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    • 2023
  • Jinhae Bay, characterized by frequent runaway ships and strong winds during typhoon attacks, poses a high risk of maritime accidents such as ship collisions and groundings. This study aims to determine a safe separation distance between ships in the Jinhae Bay anchorage, considering the unique environmental characteristics of the Korean sea area. Analysis revealed that an average of 100-200 ships anchor in the typhoon avoidance area in Jinhae Bay during typhoon attacks, with approximately 70% of ships experiencing anchor dragging owing to strong external forces exceeding 25 m/s wind speeds. In this study, we analyzed and presented the separation distances between ships during anchoring operations based on domestic and international design standards, separation distances between ships used as actual typhoon shelters in Jinhae Bay, and appropriate safe distances for ships drifting under strong external forces. The analysis indicated that considering the minimum criteria based on the design standards and emergency response time, a minimum safe distance of approximately 400-900 m was required. In cases where ample space was available, the separation distance was recommended to be set between 700 to 900 m. The findings of this study are anticipated to contribute to the development of guidelines for establishing safe separation distances between ships seeking refuge from typhoons in Jinhae Bay in the future.